Trigger finger
Trigger finger, also known as stenosing tenosynovitis, is a disorder characterized by catching or locking of the involved finger in full or near full flexion, typically with force. There may be tenderness in the palm of the hand near the last skin crease (distal palmar crease). The name "trigger finger" may refer to the motion of "catching" like a trigger on a gun. The ring finger and thumb are most commonly affected.
| Trigger finger | |
|---|---|
| Other names | Historicopous, trigger digit, trigger thumb, stenosing tenosynovitis |
| An example of trigger finger affecting the ring finger | |
| Specialty | Hand surgery, orthopedic surgery, and plastic surgery |
| Symptoms | Catching or locking of the involved finger, pain |
| Usual onset | 50s to 60s years old |
| Risk factors | Generally idiopathic, meaning no known cause. Perhaps diabetes |
| Diagnostic method | Symptoms and signs |
| Differential diagnosis | Sagittal band rupture |
| Treatment | Steroid injections, surgery. The role of splint immobilization is uncertain |
| Frequency | Relatively common |
The problem is generally idiopathic (no known cause). People with diabetes might be relatively prone to trigger finger. The pathophysiology is enlargement of the flexor tendon and the A1 pulley of the tendon sheath. While often referred to as a type of stenosing tenosynovitis (which implies inflammation) the pathology is mucoid degeneration. Mucoid degeneration is when fibrous tissue such as tendon has less organized collagen, more abundant extra-cellular matrix, and changes in the cells (fibrocytes) to act and look more like cartilage cells (chondroid metaplasia). Diagnosis is typically based on symptoms and signs after excluding other possible causes.
Trigger digits can resolve without treatment. Treatment options that are disease modifying include steroid injections and surgery. Splinting immobilization of the finger may or may not be disease modifying.